fa_le

Hi, This film is very nice and cheap compared to other brands. If you use it as normal panchromatic film the results are very good. The grain is peculiar with funny rounded dendrites. The point about infrared focusing mark is a question of Fresnel coefficient and light wavelength. Different colours of light (wavelength) do not propagate with the same angle in such a material. Normal lenses are made to cope with visible light. So if you use the film with visible light no focus correction is required. If you do infrared then you need to use the IR marking to compensate for different light propagation angle in the lenses. I shot a few of those films. I used A Cokin A007(89B) filter. This filter is quite affordable. The only thing to be cautious about is to use your hand as a sunshade to avoid reflection on the back of the filter. I developed the film 6 minutes in D76 stock, Foma (stinky) stop bath, and 4 minutes of Ilford rapid fixer. It gave good results. For exposure, camera set on 400ISO, filter on, I followed the camera cell metering. I took one correct exposure then bracketed to over and under for 1 stop. The one stop over exposure is usually the best. Lately I went on Rollei web page. They suggest setting the camera to 25 ISO and make the measure without the filter. I should try that next time. Have fun and show us the results.